The proposed intervention will be specifically designed to meet the needs of young adolescent girls and to prevent or minimize the decline in physical activity that frequently occurs during adolescence. Social Cognitive Theory will be used to guide the intervention and evaluation; personal, behavioral, and socio-environmental factors hypothesized to be correlates of physical activity will be the targets of the intervention. The intervention will include changes in the structure and organization of physical education classes, a classroom-based PA competition, a school- based Physical Activity Advisory Council, parental involvement, and community-based programming. Measurements will be taken at baseline (end of 6th grade), following the first and second years of program implementation (end of 7th and 8th grades), and one-year following program completion (end of 9th grade). Schools will be recruited and randomized to treatment or control condition. The study proposes an inexpensive sub-study to investigate dietary intake as it relates to PA, one of the first population-based studies to examine diet and PA simultaneously. In addition, the sub-study will also provide important information on PA patterns throughout the year. The school portion of the intervention will consist of offering girls a choice between two physical education curriculum options. One option will be modeled after the CATCH PE approach, but adapted to a co-educational middle school setting, focused on increasing the amount of time spent in moderate to vigorous physical activity (MVPA) during standard physical education activities. The other option will be a Girls Only Option physical education class focused on individualized activities rather than competitive activities while increasing the amount of time girls spend in MVPA during PE class. The classroom component will complement the PE program and provide incentives for after-school physical activity. The community link will concentrate on bringing community partners to the school to reduce barriers to participating in community PA opportunities and increasing the perceived accessibility of those opportunities. Summer activities will include options for attendance at a fitness/wilderness camp experience during the summer between 7th and 8th grades. Additional intervention activities include a family component featuring coupons with behavioral cues and incentives for increasing PA levels of families, a PA competition administered through health class, and interactive websites for students, school staff and families.